1. Field of the Invention
The present invention relates generally to cassettes of the type including a length of magnetic tape wound around at least one reel rotatably mounted in a housing, with a portion of the tape extending to the exterior of the cassette for engagement by a recording and/or reproducing device and, in particular, a slack limiter for frictionally engaging the tape and limiting looseness or slack in the portion of the tape extending exteriorly of the cassette.
2. Description of the Prior Art
In cassettes including at least one reel of tape for data recording, slack or looseness can arise when the cassette is being transported or is otherwise separated from its associated recording and/or reproducing device (hereinafter recorder). While some cassettes have locks which restrict rotation of the reel or reels when the cassette is not in the recorder, it is still possible that one or both of the reels, if the cassette is furnished with two reels, within the cassette housing may turn to unwind tape and develop slack in the portion of the tape extending from the reel. Slack in the tape can also occur when the tape is engaged with the recorder. Typically, the recorder has a spindle or spindles which engage the tape reel or reels. If the cassette has two reels and driving and braking of the reels during operation of the recorder is not synchronous, slack in the tape will develop. This slack may cause the tape to jam within the cassette housing or within the recorder and may lead to defective recording or reproducing operations.
So-called slack limiters for avoiding such slack or looseness of the magnetic tape have been disclosed in U.S. Pat. Nos. 4,304,374; 4,405,097; 4,417,704 and 4,518,135 in which the slack limiters described commonly include a resilient, flexible strip, usually of plastic, affixed at one end to the cassette housing and having a free end to which is adhesively affixed a layer of low friction material such as polytetrafluoroethylene (Teflon). The free end of the slack limiter presses the magnetic tape against a stationary portion of the cassette housing and thus frictionally prevents the tape from unwinding from the reel and developing slack.
The foregoing patents are distinguished by the manner in which the slack limiter is attached to the cassette housing. Although slack limiters such as those described in the above patents have generally performed satisfactorily, the potential for a number of problems exists. The slack limiter may become detached from its mounting, particularly if the slack limiter is adhesively mounted, and may fall from or within the cassette housing. Additionally, the adhesive securing the Teflon coating to the slack limiter may deteriorate or fail allowing Teflon or adhesive pieces to be present within the cassette housing.